If you go to the websites of the players
(
http://www.apple.com/quicktime/ &
http://uk.real.com/index-direct.html?lang=en-gb&loc=gb )
you should be able to download them, for free from thier.
You may have to look at the settings in the players and make one of them your default so that when you download media, it will automaticly play it in Real Player or Quciktime.
Hope this works and makes sense.
Regards
Luke